Size

• According to the Population Reference Bureau, 8 percent of Americans live in cities with a population of one million or more.
  
  

Identification

• The U.S. Census Bureau defines an urban area solely upon the population density of block groups. A block group is a statistical subdivision within a census tract and typically contains between 300 and 3,000 people.
  
  

Considerations

• Urban settlements require more infrastructure than rural areas. More sewers, roads and public-lighting fixtures are required to maintain safe and sanitary conditions for urban dwellers.
  
  

Potential

• Many urban settlements contain racially, ethnically and culturally diverse populations.
  
  

Function

• New York City passed the first zoning laws in the United States in 1916. The regulations sought to shape development for the rapidly growing urban population.